Control device



, March 1963 w. A. BIERMANN ETAL 3,080,143

CONTROL DEVICE 4 Sheets-Sheet 1 Filed July 30. 1959 34 Fm. l

2 INVENTORS WlLuAM A.B\ERMAN|-| ROBERT P\'.BAUER B LQURDELS V. MCARTYATTORNEY March 5, 1963 w. A. BIERMANN ETAL 3,080,143

CONTROL DEVICE Filed July 30, 1959 4 Sheets-Sheet 2 4-2. l 40 Fla. 3

4-4 I, l l v ll "1 I I Ill I so INVENTORS WHJJAM A. BIERMANN Roses-r R.BAUER LOURDES V. MCARTY Fla. 6 ATTQFRHEY March 1963 w. A. BIERMANN ETAL3,

CONTROL DEVICE Filed July 30. 1,959 4 Sheets-Sheet 3 i Fla. 7

20 14- z II 30 2 Fleas \HVENTORS W\LLIAM A. BIERMANN ROBERT R.8AUERLOURDES V. MCARTY BY 2 4 y E ATTQRNEY March 5, 1 3 w. A. BIERMANN ETAL3,080,143

CONTROL DEVICE 7 Filed July 30, 1959 1 4 Sheets-Sheet 4 7b 35 b2 I W 475b4- d e 50 7o r a 44 f I I g I 7 33 3o 34 2b a: ANT\C\PATED LINE,SWWCH THERMOSTAT UPPER HOT ROD H Fl uwzaeg PH INVENTORS i W\LL\AM A.BIERMANN 1 ROBERT R.6AUER HI Louaoes V. MCARTY ATTORNEY United StatesPatent Ofitice insane Patented Mar. 5, T953 CGNTRGL DEVICE William A.Biermann, lirooinield, Robert R. Earner, New

Berlin, and Lourdes V. McCarty, Milwaukee, Wis, assignors to ControlsCompany of America, Schiller larlr, Ilh, a corporation of Delaware Fiied.luly 3t 1959, Ser. No. $30,572 6 Claims. (til. 251--11) This inventionrelates to a fuel flow control device, and particularly to a control forregulating oil flow to vaporizing burners.

The principal objection to pot type burners is the soot accumulationresulting from the poor combustion characteristics of the fuel underdifferent operating conditions within the burner. During the ofi cycle,the burner is generally operated with micro-pilot flow or no flow whichrequires electrical ignition. In either case, the heat generated in thepot is insutlicient to vaporize a large quantity of oil. Hence, when thethermostat calls for heat, poor combustion will result if the fuel flowis established rapidly. Thus the incoming oil is not adequatelyvaporized and the tiarne becomes smoky. If, on the other hand, thecontrol provides a low fuel flow rate (as distinct from the very low ormicro condition), the burner can adequately vaporize the incoming oil toassure a clean flame which will in turn heat the pot sufficiently tovaporize a higher flow rate if and when provided. With the potpreheated, the flow rate can be increased graduaily until full iiow hasbeen reached without going through a smoky condition.

The primary object of this invention is to provide a iuei flow controlwhich will regulate the flow to the burner in accordance with the aboveoutlined desirable conditions.

- A further object of this invention is to provide a control whichsubstantially reduces the number of times this critical range ofoperation must be passed through.

The above objects are accomplished with the control which will bedescribed in detail hereinafter. This control is compatible with use inconjunction with either no iiow or micro-pilot fiow during the oiicycle. When the thermostat calls for heat, the flow rate will beincreased to a low iire condition and held at that rate. The oil flowinginto the pot will be adequately vaporized at this flow rate and will, inturn, generate enough heat in the pot to handle increased flow which thecontrol will provide after the flow rate has been maintained at low flowlong enough to heat the pot. The flow rate thereupon increases graduallyto full how and will remain at full flow under control of the roomthermostat. When the thermostat is satisfied, the flow rate will begradually decreased to the low flow rate condition. The present controlwill, however, maintain this low flow rate condition for some period oftime during which the room thermostat may call for heat. if thethermostat does not call for heat, the control will ultimately reducethe flow rate rapidly to micro-pilot or ofi. Under normal heat loads,the thermostat will call for heat again and the smoky stage iscompletely avoided since the low flow rate keeps the burner hot.

Other objects and advantages will be pointed out in, or be apparent fromthe specifications and claims as will obvious modifications of thesingle embodiment shown in the drawings in which:

FIGURE 1 is a plan view of the present invention with the cover removed.

FIGURE 2 is a side view partly broken away showing the presentinvention.

FIGURE 3 is an end view of the present invention.

FIGURE 4 is another end view of the present invention.

FiGURE 5 is taken along 5-5 of FIGURE 2 showing the bimetal heater.

FIGURE 6 is a detail of the low flow regulator.

FIGURE 7 shows the present invention with a limit control energized.

FEGURE 8 shows the parts in the positions assumed at low flow.

FIGURE 9 shows the parts at high fire.

FIGURE 10 shows the control shortly after the thermostat opens.

FIGURE ll shows the wiring diagram for the control.

FIGURE 2 shows a constant level oil control device of the type having aflow control inlet valve 1%) to maintain a constant level of fuel incasing 11. The constant level control includes an outlet valve assembly12 having a standpipe 14 provided with port 16 with which metering slot13 on the lower end of valve stem 29 registers to provide the desiredflow rate. open by spring 22 compressed between the upper end of thestandpipe and valve shoulder 24. It will be noticed that lever 26 actsagainst the valve shoulder to over-ride the bias of the spring 22,holding the valve closed. This lever is part of the limit controlprovided by this assembly and is pivoted on cover plate 28 and biaseddownwardly by spring 3%. The upstanding end 32 of the lever has a socketin which the right hand end of hot rod 34 is fitted, the other end ofwhich is fixed to the upwardly sheared stationary bracket 33. The hotrod has a resistance heater wound thereon to expand the rod whenenergized and rock the lever about its pivot to lift the left end of thelever oii the valve shoulder and permit the valve to open, if allowed todo so by the other control apparatus. The hot rod and lever provide alimit control (for stack temperature or other condition) which isconstantly energized and the circuit to the resistance heater will bebroken upon the stack temperature exceeding a pre-selected temperaturefor the control. At this point the hot rod will cool and spring 36' willforce the lever down to over-ride the bias of spring 22 and close theoutlet valve. It will be obvious that the action of the resistanceheater circuit could be reversed to provide for heating the hot rod uponthe dangerous condition occurring. The illustrated form is preferredsince it fails safe in the event of power failure.

The upper end of the valve stem proiects through aperture 37 in thecover and, in the position shown in FIG- UEE 7, bears against the bottomend of pin 35 depending from lever 36. This lever is pivoted on pin idsupported in the mounting bracket 42. Spring d4 urges the lever 36downwardly against the valve stem, while the upstanding right-hand endas of the lever is acted upon by hot rod connected thereto throughadjustable socket 5i and having the other end abutting depending flange52 on the mounting bracket. When this hot nod is energized is will beappreciated that there is considerable mo tion multiplication due to thelever arms involved and this multiplication plus the rapid response or"the hot rod will rapidly lift the lever and hence pin 35 from the upperend of the valve stem. The valve stem will rise due to the bias ofspring 22 until it contacts the flow regulator lever 54 as shown inFIGURE 8.

A slow response lever 56 is under the control of heater 53 mounted onheavy metal bar as which acts as a heat sink connected at its right endto the mounting bracket. The heat from the heater must first betransferred to the heat sink and from there to bimetal 62 to warp thebi-' metal arm upwardly. The left hand end of the bimetal is providedwith a yoke 64 engaging the end of lever 56. This lever is pivoted onpin so and extends upwardly The valve stem is biased assures over thepivot point to the left and is bent down in back to engage the yokecarried by the bimetal. As the lever 56 moves upwardly about its pivot,it carries U shaped bracket as with it. Bracket 68 is biased by spring74 so that as the lever 56 moves upwardly, it pivots on the shoulder 72of the bent back portion of the lever 56 until the T arm 7'5 of thebracket engages the lever. This action may be seen clearly by comparisonof FIG- URES s and 9. FIGURE 9 shows the limit er clockwise motion ofthe U shaped bracket about its pivot. As this bracket rocksabout theshoulder, it eventually relieves the pressure on the fuel regulatinglever to permit the lever to rock about its fulcrum under the influenceof hair spring 74 and the valve spring 22.

In the position shown in FIGURE 9, it will be noted that the upper leftend of the U shaped bracket has moved into the arcuate path of the freeend of fast acting lever 36. Upon de-energizing the upper hot rod, thefast acting lever will swing down and would normally shut off fuel flowrapidly but latch '76 provided on the upper end of the U bracket willcatch the lever and hold it in the upper position until the lever 56 hasbeen returned to the low flow position by the bimetal and the U bracketstarts to pivot until the fast acting lever is released from the latch.The bimetal is relatively slow acting since the heat sink must also cooldown producing a slow reduction in fuel flow rate and may actually holdit at low fuelflowrate for'aperiod of time. In the absence of a newthermostatic demand for heat in this period of time, the lever will snapdown to either cutoff the flow or reduce itto micro-pilot conditions.This time delay before cu off gives a modulating action. Thus when theflow rate has beenreduced'to low and has remained there for a shortperiod of time and the thermostat calls for heat, the flame can berapidly increased, compatible with the response characteristics of thebime'tal heat sink, to the high flow condition. Under normal heat loads,the control eliminates going through the troublesome combustion stagesmentioned above. However, if it is a mild day, and the thermostat doesnot call for heat within the period of time provided by the control, thecontrol will then snap the flow rate to off or micro-pilot and thus gothrough the sooty stage fast enough to avoid any difficulties incombustion.

At the low fuel flow rate, the air for combustion is normally suppliedto the burner by natural draft. As the valve is opened to increased thefuel flow, a point Will be:- reached where the natural draft will not besufficient to nroduce complete combustion within the burner. The controlis calibrated so that at a point in the upward movement-of lever 56, fanswitch 77' will be actuated by finger 78 pivoted on pin 86 and: biasedupward by spring 82. The finger engages a calibration screw 84 in lever56 so that the point in the fuel flow rate which requires additional aircan be adjusted to meet any operating conditions.

FIGURE ll shows the wiring diagram for the above described control. Theoperation is obvious in view of the above and the legends appliedthereto. From the above description and wiring diagram it will beappreciated that other control devices may be utilized to achieve thesame result. The most obvious would be to utilize a fast acting bimetalin place of the upper hot rod 48. It should also be appreciated that anyfast acting motor device such as a solenoid could be used in lieu of theupper hot rod. Using a solenoid would of course require the addition ofa transfer or holding switch that would be regulated by the slow actingbimetal. A slow acting bimetal would regulate the control between lowand highwith the solenoid over-riding the bimetal between low and 0E.Other changes should be apparent from the specification and claims.

It will be appreciated that before the control operates, lme-switch 88and limit switch 90 must be closed to energize the lower hot rod 34 tohold the lever 26 in position where it will not interfere with themovement of the valve stem 2%. When thermostat $2 is satisfied the partswill be in the position shown, either being off or at micro-pilot. Nowwhen the thermostat calls for heat, the fast acting lever 36 controlledby the upper hot rod 48 will rapidly risenout of the way (FIGURE 8)permitting the valve stem to come up to the flow regulator 54 where itis detained until the heat given off by heater 58 mounted on the heatsink 69 can be transferred to the bime tal 62 which will gradually;actuate lever 56 and permit the flow regulator lever 54 to slowly moveto the position shown in FIGURE 9 where high fuel flow rate has beenreached. Upon satisfaction of the thermostat, the upper hot rod istie-energized and cools rapidly, allowing the fast acting lever to reston the catch on bracket 68 so that control of the return motion of thevalve stem is retained. by the slow acting. bimetal arm rather thanhaving the fast acting lever snap the valve shut. This permits a gradualdecrease in the flow rate to the low flow position and, by properadjustment of latch 76'carriedby the bracket, a desired time lag can beprovided at low fuel flow before the fast acting lever 36-is released toshut off fuel fiow. If a new demand for heat isimade by thethermostatduring this time delay, the fuel flow rate will be. gradually increased.

This type of control avoids the objectionable sooty. condition when thethermostat calls for heat and under normal heat demand will not allowthe control to go to off or micro-pilot, achieving a degree of heatmodulation not normally found in thermostaticallycontrolled devices.When an anticipated thermostat is coupled with this control, the flowcontrol device will not, under normal heat demand, go to the low flowrate, but will come down to some intermediate, level whereupon theanticipated thermostat, which is inherently faster cycling than anunanticipated thermostat, will renew the call for heat and bring theflow back-up. Hence the combination of. an anticipate-d thermostat withthis control will tend to modulate the oil flow at a level above the lowflow rate which level will be determined by the heat demand for the day.Hence, on a very cold day, the modulation will take place very near thehigh range of flow while on a milder day the modulation will range overawider variation in flow rate.

Although but one embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may bemade therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

l; A fuel-flow control comprising a valve for regulatopening direction,fast and slow acting valve operating means b'Othfl'BSPUI'lSlVC to acontrol condition to allow the valve to move in thevalveopening'direotion, the slow acting valve operating means acting on thevalve at a low flow position to take control of the valve from the fastacting valve operating means, the slow acting valve operating meansthereafter regulating motion of the valve be tween low andhigh firepositions of the valve, and means carried by the slow acting operatingmeans for engaging the fast acting operating meansupon termination ofthe control condition to prevent operation of the fast acting operatingmeans, said engaging means releasing the fast acting operating means forclosure of the valve after the slow acting operating means has closedthe valve to a predetermined position.

2; A control accor'ding' to claim 1 in which said engaging means doesnot release the fast acting operating means until the slow actingoperating means has reached said predetermined position and hasbeenmaintained in that position for a predetermined period of time.

3. A fuel flow control comprising, a valve for controlling the flow offuel, said valve being biased in the valve opening direction, first heatmotor means positioned to engage the valve and responsive to a controlcondition to allow the valve to move to an open position, second heatmotor means responsive to a control condition holding the valve to a lowfuel flow rate position, said holding means gradually allowing the valveto move to a high flow rate position in response to the controlcondition, means carried by the second heat motor means for preventingthe first heat motor means from closing the valve in the absence of thecontrol condition, said second heat motor means gradually returning thevalve to the low fuel flow rate position in the absence of the controlcondition, and said preventing means releasing the first heat motormeans to close the valve after the valve has been returned to the lowflow rate position.

4. A fuel flow control comprising, a valve movable between minimum andmaximum flow positions, bimetal means operative to regulate the movementof the valve between a flow rate intermediate the minimum and maximumflow positions, said bimetal means being responsive to a controlcondition and acting at a predetermined gradual rate when bothincreasing and decreasing the flow control, and a hot rod meansoperative to move the valve rapidly between the minimum flow position ofthe valve and said intermediate position, and a second fast acting hotrod means positioned to engage the valve and responsive to a secondcontrol condition to move the valve to the minimum flow position.

5. A fuel flow control comprising a valve for controlling the flow offuel, said valve being biased in a valve opening direction, a firstelectrically energizable valve operator means normally biased to holdthe valve closed and adapted to be electrically energized to move to aposition clear of the valve allowing the valve to move freely to an openposition under the influence of the opening bias, a second electricallyenergized valve operator means normally operable to limit said freeopening movement of the valve under the influence of its opening bias toa low fuel flow rate position, said second valve operator includingmeans to limit the opening movement of the valve between low fuel rateposition and maximum flow rate position to a predetermined rate ofmovement, said second valve operator including time delay means forholding the valve at low fuel position for a predetermined period oftime during closing movement of the valve from maximum flow rateposition to low flow rate position, said time delay means of the secondvalve operator engaging and restricting movement of the first valveoperator in valve closing direction when the first and second valveoperators are de-energized so that the second valve operator thereaftercontrols and gradually moves the valve to low flow rate position.

6. A control according of claim 5 wherein said time delay means releasesthe first valve operator to quickly snap the valve to closed positionafter the valve has been returned to the low flow position for apredetermined time interval.

References Cited in the file of this patent UNITED STATES PATENTS1,697,432 Martin Jan. 1, 1929 2,116,605 Kelly May 10, 1938 2,118,443McCorkle May 24, 1938 2,335,212 Landon NOV. 23, 1943 2,355,436 Hay-terAug. 8, 1944 2,373,324 Marti-n Apr. 10, 1945 2,461,615 Taylor Feb. 15,1949 2,582,334 Huntley Jan. 15, 1952 2,608,996 Forman Sept. 2, 19522,703,606 Johnson et al. Mar. 8, 1955

1. A FUEL FLOW CONTROL COMPRISING A VALVE FOR REGULAING FLOW TO ABURNER, SAID VALVE BEING BIASED IN A VALVE OPENING DIRECTION, FAST ANDSLOW ACTING VALVE OPERATING MEANS BOTH RESPONSIVE TO A CONTROL CONDITIONTO ALLOW THE VALVE TO MOVE IN THE VALVE OPENING DIRECTION, THE SLOWACTING VALVE OPERATING MEANS ACTING ON THE VALVE AT A LOW FLOW POSITIONTO TAKE CONTROL OF THE VALVE FROM THE FAST ACTING VALVE OPERATING MEANS,THE SLOW ACTING VALVE OPERATING MEANS THEREAFTER REGULATING MOTION OFTHE VALVE BETWEEN LOW AND HIGH FIRE POSITIONS OF THE VALVE, AND MEANS